If x – y = 8 and xy = 5, find x2 + y2.

If x – y = 8 and xy = 5, find x² + y².

Answer :

We know that

(x – y)² = x² + y² – 2xy

It can be written as

x² + y² = (x – y)² + 2xy

It is given that

x – y = 8 and xy = 5

Substituting the values

x² + y² = 8² + 2 × 5

So we get

= 64 + 10

= 74

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